FUEL OILS FOR DETROIT DIESEL ENGINES
DIESEL FUEL OILS
cetane fuel. If this condition is allowed to continue for any
prolonged period, harmful fuel derived deposits will
The quality of fuel oil used for high-speed diesel engine
accumulate within the combustion chamber. Consult the
operation is a very Important factor In obtaining satisfactory
FUEL OIL SELECTION CHART.
engine performance, long engine life, and accept
DISTILLATION END POINT
COMPLETELY DISTILLED FLUID
Fuel can be burned In an engine only alter it has been
Fuel selected should be completely distilled material. That is,
vaporized. The temperature at which fuel is completely
the fuel should show at least 98% by volume recovery when
vaporized is described as the distillation end point (ASTM D-
subjected to ASTM D-86 distillation. Fuels marketed to meet
86). The distillation (boiling) range of diesel) fuels should be
Federal Specification VV-F-800 (grades DF-1 and DF-2) and
low enough to permit complete vaporization at combustion
ASTM Designation D-975 (grades 1-D and 2-D) meet the
The combustion chamber
completely distilled criteria. The differences In properties of
temperature depends on ambient temperature, engine speed,
VV-F-800 and ASTM D-975 fuels are shown in the following
and load. Mediocre to poor vaporization Is more apt to occur
during severe cold weather and/or prolonged engine idling
FEDERAL SPECIFICATION & ASTM
and/or light load operation. Therefore, engines will show
DIESEL FUEL PROPERTIES
better performance operating under the conditions described
above when lower distillation end point fuels are used.
Consult the FUEL OIL SELECTION CHART.
The cloud point is that temperature at which wax crystals
Flash Point, min.
begin to form in diesel fuel. The selection of a suitable fuel for
Carbon Residue (10%
low temperature operability is the responsibility of the fuel
residuum) % max.
supplier and the engine user.
Consult the FUEL OIL
Water & Sediment, % by
Ash, % by wt., max.
FUEL OIL SELECTION CHART
90% by vol. recovery, min
End Point, max.
Viscosity 100 (38 )
Kinematic, cSt, min.
Saybolt, SUS, min.
Winter No. 2-D*
Kinematic, cSt, max.
Saybolt, SUS, max.
Sulfur, % by wt., max.
Summer No. 2-
Winter No. 2-F
tanks and stored fuel should be inspected regularly for dirt,
Summer No. 2-
water or water-emulsion sludge, and cleaned if contaminated.
Storage instability of the fuel can lead to the formation of
varnish or sludge in the tank. The presence of these
the fuel supplier.
*No. 2-D diesel fuse may be used in City coach engine models that have been
FUEL SULFUR CONTENT
certified to pass Federal and California emission standards.
The sulfur content of the fuel should be as low as possible to
The cloud point should be 10 (0 ) below the lowest expected
avoid premature wear, excessive deposit formation, and
fuel temperatures to prevent clogging of the fuel filters by wax
minimize the sulfur dioxide exhausted into the atmosphere.
Limited amounts can be tolerated, but the amount of sulfur in
When prolonged idling periods or cold weather conditions below
the fuel and engine operating conditions can influence
32 (0 ) are encountered the use of lighter distillate fuels may
corrosion and deposit formation tendencies.
be more practical. The same consideration must be made when
The deleterious effect of burning high sulfur fuel is reflected in
operating at altitudes above 5,000 ft.
Detroit Diesel lube oil change interval recommendations.
Detroit Diesel recommends that the Total Base Number (TBN-
DETROIT DIESEL FUEL OIL SPECIFICATIONS
ASTM D 664) of the lube oil be monitored frequently and that
Detroit Diesel Allison designs, develops and manufactures
the oil drain interval be drastically reduced. Consult the FUEL
commercial diesel engines to operate on diesel fuels
OIL SELECTION CHART.
class)fled by the ASTM as Designation D-975 (grades 1 -D
IGNITION QUALITY - CETANE NUMBER
and 2-D). These grades are very similar to grades DF-1 aru3
There is a delay between the time the fuel is injected into the
DF-2 of Federal Specification VV-F.800.
cylinder and the time that ignition occurs. The duration of this
Burner fuels (furnace oils or domestic heating fuels) generally
delay is expressed In terms of cetane number (rating).
require an open flame for satisfactory combustion. The
Rapidly ignited fuels have high cetane numbers; e.g., 50.
ignition quality (cetane rating) of burner fuels (ASTM D-396) is
Slowly ignited fuels have low cetane numbers; e.g., 40 or less,
poor when compared to diesel) fuels (ASTM D-975).
The lower the ambient temperature, the greater the need for a
In some regions, however, fuel suppliers may distribute one
fuel that will ignite rapidly; i.e., high cetane.
curd that is marketed as either diesel fuel (ASTM D-975) or
Difficult starting may be experienced it the cetane number of
domestic heating fuel (ASTM D-396) some times identified as
the fuel is too low. Furthermore, engine knock and puffs of
burner, furnace, or residual fuel, Under these circumstances,
white smoke may be experienced during engine warm-up
the fuel should be investigated
especially In severe cold weather when operating with a low